ML20214N296
| ML20214N296 | |
| Person / Time | |
|---|---|
| Issue date: | 07/17/1986 |
| From: | Knapp M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Themelis J ENERGY, DEPT. OF |
| References | |
| REF-WM-68 NUDOCS 8609160225 | |
| Download: ML20214N296 (5) | |
Text
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WM68 r/f M Nataraja WMLU r/f DM Gillen RE Browning GN Gnugnoli MR Knapp TL Johnson, GT John G. Themelis, Project Manager RD Smith S Smykowski Uranium Mill Tailings Project Office J0 Bunting M !!aisfield U.S. Department of Energy DE Martin W Ford Albuquerque Operations Office P Justus J Kane P. O. Box 5400 JT Greeves Albuquerque, New Mexico 87115 M Fliegel
Dear Mr. Themelis:
Jolene Garcia of your staff requested input from NRC regarding the draft CADSAR for the Green River UMTRAP site.
In order to provide her with this input, an abbreviated list of observations and concerns was telefaxed directly to her on July 1, 1986 prior to her departure for the site familiarity visit.
Enclosed is a more detailed explanation of these comments which I hope will prove to be useful in preparing the final CADSAR.
Sincerely,
/s Malcolm R. Knapp, Chief Low-Level Waste and Uranium Recovery Projects Branch Division of Waste Management Office of Nuclear Material Safety and Safeguards
Enclosure:
As stated i
cc:
J. Garcia. 00E/AL J. Turi, DOE / liq Record Note: The telefaxed information and this transmittal and enclosures havebeenpreparedincoordinationwithT.L. Johnson (WMGT)andA.S.Smykowski (WMEG).
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o ENCLOSURE GREEN RIVER, UTAH DRAFT CADSAR ENGINEERING COMMENTS 1.
Based upon review of the information contained in the CADSAR, it appears that the alternatives for relocation of the tailings for off-site stabilization have been prematurely rejected.
This decision was primarily based on high transportation costs and did not consider the key technical issues associated with each alternative.
No cost comparison has been provided which compares relocation with stabilization-in place (SIP) and stabilization-on site (505).
In summary, the draft CADSAR does not include all the key technical issues associated with each alternative which would aid in selecting an acceptable approach.
2.
As a resuIt of thb review of the S'0S alternative in the CADSAR, the NRC staff noted several key geotechnical engineering aspects. associated with SOS which were not adequately addressid nor were they compared to those issues associated with the other alternatives.
These include:
the liquefaction potential of the foundation soils, specifically the o
alluvial sands and gravels; the effects of flooding from Browns Wash on pile stability.
The PMF, o
which would indicate whether the pile could become inundated, has not been identified; the durability and size of the erosion barrier material.
It is o
uncertain whether riprap with adequate size and durability can be obtained from the riprap borrow area.
The CADSAR did not address material details about the rock nor the size of the rock that will be required for erosion protection; o
the costs for cover material have been estimated for comparative purposes; however, estimates of the thickness of the cover and the volume of material required for each alternative have not been specified; the CADSAR did not appear to address the potential for a slope o
failure and the potential for differential settlement when comparing alternatives.
3.
The final CADSAR should characterize and evaluate the borrow materials (radon barrier, gravel and riprap). Additior.',11y, it should include standard penetration test data characterizing foundation soils.
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1 CPEEN RitER, UTAH DRAFT CADSAR SURFACF WATEP FYEF0LGGY Of fESTIONS At!D CC?.VEUTS 1.
Based on a review of the inforrratirr rrraided in the CADSAR, it does not appear that the erosica prcicctier reovirements for either the stabili ction-in-place (SIP) optier cr the stabilization-on-site (505) cption have been adequately est4 rated.
For the SIP option, it appears that extensive riprap will be reeded along Brown's Wash.
For the SOS cption, it appears that extensive r'prap vill be needed both on Brown's Pash and on tha slopes whicF direct runoff from the pile to the Brown's l' ash ficooplain.
While the informatter prrvided in the CADSAR is not complete regarding ficoc ficvs crd velocities, it appears that because of the stream's alignment, floodinc or Prcyr's Wash will likely cause ccnsiderable
' erosior.'by direc+ inn #1ood flows essentia11* fcrp' ndicular to' the stream e
bank. For both the S P and frf cptions, erosion protection will be needed to prevent streambank errsicn; and to prevent migration of the channel toward the relucated tciliros. Additionally, for the SOS option, it appears that the slopes from the profescd pile to the floodplain are relatively steep (IV on Ef4 trd vill thus recuire erosion protection to stab 11ue tttn.
The situation and eroblers resec tere may be similar (but on a smaller scale) to ttcte tt the Shiprock, New Mexico site where escarpacnt stabilization and flew diversions using extensive erosion protection were required.
Fr cerclude that additional studies shculd be conducted to better assess the erosion protection designs for the two options presented.
These studies should include an assessncnt of (1) PMF peak flows, velocities, and erosion protection for Brown's Wash ard; (') the need for erosion protectice for slopes where the SOS option is used.
Based on the abcVe, it may be prudent to discess the viability and costs Associated with one or more' additional alternative sites.
2.
In general, those factors which sirr.'ficantly a'ffect the design should be carefully analyzed in the CAOS/P. Reccgr.izing that-the CADSAR is a preliminary decision-makirp dcct:rrcnt, it is nonetheless important to.
provide estimates of the erosien prctection (for example) that will be ieedcd, sirre this aspect constitutes t. large percentage of the total costs al a site like Green River. !!e consider that preliminary estimates of the FMF peak flow and selecit should hava Fern stated in the CADSAR, in' order to provide a basis for the prelirinary design and, in the case of Green River, the basis for noving the pile. fuch preliminary flood estimates oo not have to be elaborate or detailed ard can usually be estimated using very simple nodels (e.g. SCS triarrelar unit hydrograph and normal velocities) or using published es+irates of large floods (e.g. Crippen and Bue).
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3.
In general, we consider it irarprcpriate to halt the search'ior alterr. ate sites atter only one other site is ider.tified. For Green River, no other sites were identified after the EOS cption was concluded to be feasible.
It appears that, in this cose, the 50! cotier may ont be as qood as previously thought, ard ethcr sites may need to be identified Ic meet the overal' purpose ~ of the CADSAR. Regardiess of the feasibility of SOS, additional alternatives should have been provided in the CADSAR, alorp with preliminary design data, cost data, site data, and further rcccr.r.endations for detailed site investigations.
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,s GREEN RIVER, UTAH DRAFT CADSAR 4
OTHER
GENERAL COMMENT
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1.
The DOE memorandum of hovember 19, 1985 initiating the CADSAR approach established the following content items:
A.
Early Site Assessment Information B.
Remedial Action Options to be Looked at 1
C.
Preliminary Assessment of Transportation Options l
D.
Summary of Historical Infomation E.
Description of Processing and Disposal Site Characterization Activities to be Performed F.
Listing of Key Technical Issues G.
Rough Order of Magnitude Cost Estimates The NRC' staff review' concluded that for' all items except D, the information was either insufficient, underestimated cr just not clear.
t Elimination of consideration of alternatives beside SOS and SIP is not advisable based on the information and analysis presented in the CADSAR.
2.
The CADSAR text shoulo sumarize significant infomation in the BFEC Appendix. For example, the Ra-226 baselir.e soil contamination levels in the tailings, on site and off site. This would aid in characterizing he kind of radon barrier that is needed.
3.
An identification grid should be added to the BFEC Appendix to help identify locations of sample measurements.
For example, gama-ray spectroscopic data indicated levels of 822 pCf/gm Ra-226. However, it is not clear where this is located (other than six-feet in depth). This concentration appears high especially since the slimes are reported to have been removed to the Rifle site. Map identification of sampling locations is necessary for all data treasured and presented in the CADSAR.
4.
It is unclear whether well locations in figures 3.5 and 3.6 will be adequate to c".'acterize grcund-water quality for both SIP and SOS options.. The ammary of site characterization which is to be included in the final CADSAR, will ostensibly address grcund-water quality. The draft CAOSAR discussion of future ground-water characterization activities is too'brief.
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